Antenna arrangements of the above-cited type are utilized in transponders which are operated in the UHF frequency range. In such UHF transponders, the antennas are frequently configured as a dipole antenna having a chip being disposed in the center of the antenna conductor structure and being contacted with the antenna conductor structure via a terminal arrangement.
Such UHF transponders are frequently designed as so-called “tags” which are planarly connected to the surface of the product to be labeled. In this context, for the positioning of tags, such application locations can be formed for the positioning of the tags which are not subjected to the direct manipulation by the person handling the product, i.e. for instance the staff member in wholesale or retail trade reading the transponder data with the aid of a mobile reading device, or the checkout staff reading the transponder data with the aid of a reading device for the purpose of billing. Consequently, the configuration of the transponders in the form of tags in the communication between transponder and reading device in practice scarcely causes any problems.
The situation changes if transponders being equipped with a dipole antenna are disposed in the handling zone and thus complete or partial covering of the dipole antenna by a finger of the person handling the transponder may lead to a detuning of the transponder frequency, and thus may cause a functional disruption in the communication between the transponder and the reading device.
This problem is encountered in particular if transponders being equipped with a dipole antenna are arranged in a chip card, wherein due to the small dimensions of the chip card alone, there is an increased risk that the dipole antenna is at least partially covered during the handling of the card. In a chip card, the central arrangement of the transponder conventionally known from the tags firstly would result in that the chip, and here in particular the mechanically sensitive connecting region of the chip to the dipole antenna, would be arranged in the center of the bending stresses acting on the chip card.
Moreover, the small dimensions of a chip card alone result in that the chip card is regularly held so as to be clamped between the thumb and the index finger and/or the middle finger of the person handling the chip card when the chip card is grasped, in particular in such a manner that the thumb and the finger are allowed to come into abutment essentially in the center region of the chip card surface. When a UHF transponder of the above-cited type is disposed in the central arrangement known from a tag, there is a high risk that at least a partial region of the dipole antenna is covered by the thumb and at least one finger, causing the thus involved detrimental consequences for the communication between the transponder and the reading device.